A radiation worker must wear a TLD (thermoluminescence dosimeter) when the worker enters a radiation management area in order to measure exposure to a radiation dose. The TLD is a kind of dosimeter using a thermoluminescence phenomenon that occurs when a crystalline material irradiated by radiation is heated, and measures an accumulated dose for a given time period. The TLD is used as a legal dosimeter and must be stored in a predetermined TLD cabinet in a nuclear power plant.
However, there are cases that a worker does not store the TLD in the cabinet after using the TLD or the worker takes the TLD home, so an accumulated dose cannot be accurately measured, or the worker loses the TLD.
Since the TLD cabinet used in the nuclear power plant is an open system, it is possible for another worker to use the TLD besides the worker himself. Further, when the worker does not store the TLD in the cabinet, a peculiar reading for a person is frequently generated. Herein, the peculiar reading for a person means when a person falls under any of the following items: a person who has been exposed to radiation in excess of a dose limit; a person for whom it is impossible to read the level of radiation due to damage, loss, etc. of the dosimeter; or a person who has submitted the dosimeter two or more months after the replacement period prescribed by the Minister.
Particularly, when an emergency situation such as when the worker is exposed to radiation in excess or the worker is injured occurs while the radiation worker works in the radiation controlled area, the location of the worker cannot be detected. Further, since a request system for rescuing the worker is not equipped, the worker stays in danger.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.